Pot and pan washing machines, of the type used in restaurants, institutions and other eating facilities often involve a large wash tank or basin in which water is circulated about the pots and pans to provide a washing action. One such machine is described in U.S. Pat. No. 4,773,436 issued to Cantrell et al., the specification of which is incorporated herein by reference. The machine of Cantrell includes a wash tank with jets located at an elevated position along the rear wall of the wash tank. The tank is filled with water to a level above the position of the jets. Pots and pans are placed in the wash tank, and a pump is activated to draw water from within the wash tank and direct it through the jets to create a jet stream. Each jet directs its jet stream toward the bottom wall of the wash tank, the bottom wall then deflects the jet stream upward and towards the front wall of the tank. The front wall then deflects the upward moving jet stream towards the rear wall of the tank, and the rear wall deflects the jet stream downward and back towards the front wall along the bottom wall. The combination of deflections of the jet stream from the bottom, front and rear walls provides a rolling washing action within the wash tank.
The basic components of the wash tank of the pot and pan washing machine of the prior art are shown in FIG. 1. Wash tank 10 includes side walls 12 and 14, rear wall 16, front wall 18 and bottom wall 19. A pump can be attached to either side wall; in the embodiment shown in FIG. 1, pump 50 is attached to right sidewall 14. An impeller located within pump 50 is driven by electric motor 56. The impeller draws fluid into pump inlet 52 through an intake port (not shown) located in sidewall 14. The fluid is then discharged from the pump through pump outlet 54 and into outlet manifold 60. Outlet manifold 60 includes a ninety degree turn, and several other turns, to direct the fluid across the back side of rear wall 16 and out jet nozzles 20 which are protruding through and extending from rear wall 16. The intake port associated with pump inlet 52 is covered by perforated intake manifold 30. Intake manifold 30 includes handle 36 and is removably supported within wash tank 10 for easy cleaning. Intake manifold 30 fits tightly between outer runner 32 and inner runner 34, each of which extends vertically from bottom wall 19. Heating element 40 is positioned between intake manifold 30 and sidewall 14 for its protection and to maximize the use of space.
Although the prior art pot and pan washing machine disclosed in U.S. Pat. No. 4,773,436 provides an exceptional wash action, many of the components discussed above hinder the overall efficiency and performance of the machine. Several of the components of the prior art machine that hinder performance and efficiency are the pump, the intake manifold and the jet nozzles.
As discussed above, the pump of the prior art draws fluid in through pump inlet 52 in a first direction and then discharges the fluid in a direction perpendicular to the inlet direction. The path of the fluid being discharged from pump 50 must be diverted ninety degrees in a first direction, then upward and sideways across rear wall 16 to reach jet nozzles 20. Diverting the water path requires a great deal of energy, which significantly reduces the efficiency of the pump. Furthermore, a substantial amount of additional outlet manifold construction is necessary to effect the diversion of the fluid path. This additional manifold construction increases the overall cost of producing the pot and pan washing machine. Thus it is desirable to provide an improved pump for a pot and pan washing machine that streamlines the fluid path of the machine.
Another disadvantage of the pump of the prior art is that motor 56 mounts orthogonal to sidewall 14. This increases the overall footprint of the machine from side to side. As most pot and pan washing machines are of substantial length due to the use of multiple sink basins, it is of great importance to reduce the overall footprint as much as possible to maximize the use of space in a kitchen. If a pump could be designed to orient the pump motor parallel to the side of the wash tank, the side to side footprint of the machine could be reduced, thereby maximizing usable space within the kitchen.
Additionally, in the event that motor 50 requires servicing, it must be removed axially from the pump. This requires a substantial amount of space to the side of the machine to facilitate the motor removal. Unfortunately, most kitchens have a limited amount of space, and the already large footprint of the pot and pan washing machine significantly restricts the amount of unused space allotted to the side of the machine. Therefore, it is desirable to provide a pump for a pot and pan washing machine which can be removed in a direction parallel to the side wall of the machine, rather than perpendicular thereto. Additionally, it is desirable to provide such a pump, without the need for an intricate manifold arrangement.
Another component of the pot and pan machine that reduces the overall efficiency and performance of the machine is the intake manifold. Intake manifold 30 is designed to be positioned along the side of the wash tank, reducing the usable wash area within the wash tank. Also, because water is being pulled toward the side of the wash tank, pots and pans within the wash tank will tend to migrate toward the intake side. This pot migration is undesirable because it reduces the effect of the wash action of the machine as pots and pans are clumped together along one side.
Furthermore, the prior art intake manifold is not scalable. This is because, generally, the size of the wash tank is increased by increasing the length from side to side of the tank without changing the front to back width which makes up the width of intake manifold 30. As the size of the wash tank increases, so does the required flow rate of the pump. This results in an increased draw through the intake, thereby increasing the effects of pot migration and increasing the amount of debris collected by the intake manifold. Therefore, it is desirable to provide a scalable intake manifold that reduces the effect of pot migration and that does not result in increased manifold vacuum when the length of the wash tank is increased.
Another drawback of the prior art manifold is related to the purpose of the manifold, which is to prevent debris in the wash tank from reaching the pump. Much of this debris will be drawn towards and collected by the intake vacuum. Thus, intake manifold 30 is removable to allow for routine cleaning of the debris from the manifold. If the manifold is not routinely cleaned, the efficiency and performance of the pot and pan washing machine will be significantly inhibited. Therefore, it is desirable to provide an intake manifold that is essentially self cleaning.
One final component of the prior art machine is the jet nozzle. Jet nozzle 20 protrudes from rear wall 16 of the pot and pan washing machine. Thus, the effectiveness of the jet stream on objects near the rear wall of the machine is greatly reduced since the jet stream directly exiting the nozzle initiates in a position away from the rear wall. Objects near the rear wall will only be impacted by the jet stream after it has been deflected back to the rear wall from the front wall. Therefore, it is desirable to provide a jet nozzle design that will permit the jet stream exiting the nozzle to more immediately impact objects located near the rear wall of the washing machine.
In addition to the wash tank, the pot and pan washing machines systems of the prior art usually include additional sink basins or work surfaces for 1) scraping and scrapping, 2) rinsing and 3) sanitizing. All basins or work areas of a washing machine system are preferably positioned along side of each other in their order of use for more efficient operation of the washing machine (the preferred order of use is scrapping/scrapping, washing, rinsing, sanitizing). Additionally, it is often more efficient, and provides a more aesthetically pleasing appearance, to construct the entire pot and pan washing machine as a single unit at the factory. Unfortunately, such is often impossible due to installation and transportation limitations.
Very few kitchens have entrances large enough to make installation of a four basin washing machine system as a single unit practical. Therefore most pot and pan washing machines are constructed as a two-part (or more as necessary) unit which is assembled onsite during installation. As the pot and pan washing machine is preferably constructed of stainless steel, the preferred method for joining two sections of the machine into a single unit is to weld the sections together. While welding is a rather routine method of construction at the factory, it is not very practical for onsite assembly and installation. This is due to the difficulty of transporting and operating proper welding and grinding equipment onsite to make a smooth weld. Therefore, seams that are welded onsite generally tend to have a less than desirable appearance.
An alternative to welding two sections of a washing machine system together is to bolt the two sections together. Most often a bolted connection is as unattractive as, or even more unattractive than, a poorly welded seam. Additionally, because a bolted connection results in a slight gap between the two sections of the washing machine system in which debris may collect, NSF standards require the inclusion of a two inch gap between the sections to facilitate cleaning. This results in a even greater reduction in the aesthetic appearance of the washing machine system and increases the size of the footprint of the system, or else reduces the usable volume of the basins. Therefore it is desirable to develop an attractive, non-welded field joint for assembling multiple components of a washing machine system into a single unit having no gaps between the joined components.